﻿// Copyright (c) 2008 MySQL AB, 2008-2009 Sun Microsystems, Inc.
//
// MySQL Connector/NET is licensed under the terms of the GPLv2
// <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most 
// MySQL Connectors. There are special exceptions to the terms and 
// conditions of the GPLv2 as it is applied to this software, see the 
// FLOSS License Exception
// <http://www.mysql.com/about/legal/licensing/foss-exception.html>.
//
// This program is free software; you can redistribute it and/or modify 
// it under the terms of the GNU General Public License as published 
// by the Free Software Foundation; version 2 of the License.
//
// This program is distributed in the hope that it will be useful, but 
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 
// for more details.
//
// You should have received a copy of the GNU General Public License along 
// with this program; if not, write to the Free Software Foundation, Inc., 
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace MySql.Data.Entity
{
    abstract class InputFragment : SqlFragment 
    {
        // not all input classes will support two inputs but union and join do
        // in cases where only one input is used, Left is it
        public InputFragment Left;
        public InputFragment Right;

        public InputFragment()
        {
        }

        public InputFragment(string name)
        {
            Name = name;
        }

        public string Name { get; set; }
        public bool IsWrapped { get; private set; }

        public virtual SqlFragment GetProperty(string propertyName)
        {
            if (Left != null && Left.Name == propertyName) return Left;
            if (Right != null && Right.Name == propertyName) return Right;
            return null;
        }

        public virtual void Wrap(Scope scope)
        {
            IsWrapped = true;

            if (scope == null) return;
            if (Left != null)
                scope.Remove(Left);
            if (Right != null)
                scope.Remove(Right);
        }

        public virtual void WriteInnerSql(StringBuilder sql)
        {
        }

        public override void WriteSql(StringBuilder sql)
        {
            if (IsWrapped)
                sql.Append("(");
            WriteInnerSql(sql);
            if (IsWrapped)
                sql.Append(")");
            if (Name == null) return;
            if (this is TableFragment ||
                (IsWrapped && !(this is JoinFragment)))
                sql.AppendFormat(" AS {0}", QuoteIdentifier(Name));
        }
    }
}
